It is known to provide dentifrice compositions including a source of metal ions for delivery to the oral cavity during brushing of the teeth. Such metal ions can act as therapeutic agents. Some metal ions tend to be unstable in dentifrice compositions, particularly when the dentifrice composition includes components with which the metal ions may react during manufacture or storage of the dentifrice composition prior to use. This reduces the delivery and bioavailability of the metal ions at the oral surfaces during brushing of the teeth when using the dentifrice.
U.S. Pat. No. 6,669,929 (Boyd et al.) and the related U.S. Patent Application Publication Nos. 2004/0126332 and 2008/0138369 disclose a dentifrice containing functional film flakes. The film flakes are formed of a water hydratable film which forms a matrix having entrained therein a constituent which may be a therapeutic material, or a cosmetic or decorative material. A number of therapeutic materials are disclosed, including fluoride salts as anticavities agents, calcium salts, anticalculus agents and other active agents including antibacterial agents, breath freshening agents, desensitizers, vitamins, herbs, whitening agents, high cleaning silica, preservatives, silicones or chlorophyll compounds. The breath freshening agents identified are zinc gluconate, zinc citrate and/or alpha ionone.
There is a need in the art to provide an improved dentifrice composition capable of enhancing the delivery and bioavailability of metal ions at the oral surfaces during brushing of the teeth when using the dentifrice.
There is a further need to enhance the delivery and bioavailability of metal ions such as zinc, stannous, and copper from a dentifrice, while maintaining stability in a low water dentifrice.